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| Mazumdar, A.; Dewangan, P.; Joaeo, H. M.; Peketi, A.; Khosla, V. R.; Kocherla, M.; Badesab, F. K.; Joshi, R. K.; Roxanne, P.; Ramamurty, P. B.; Karisiddaiah, S. M.; Patil, D. J.; Dayal, A. M.; Ramprasad, T.; Hawkesworth, C. J.; Avanzinelli, R.. |
| We report evidence of paleo-cold seep associated activities, preserved in methane-derived carbonates in association with chemosynthetic clams (Calyptogena sp.) from a sediment core in the Krishna-Godavari basin, Bay of Bengal. Visual observations and calculations based on high-resolution wet bulk density profile of a core collected on board R/V Marion Dufresne (May 2007) show zones of sharp increase in carbonate content (10-55 vol%) within 16-20 meters below seafloor (mbsf). The presence of Calyptogena clam shells, chimneys, shell breccias with high Mg calcite cement, and pyrite within this zone suggest seepage of methane and sulfide-bearing fluid to the seafloor in the past. Highly depleted carbon isotopic values (delta(13)C ranges from -41 to -52% VPDB)... |
| Tipo: Text |
Palavras-chave: Methane hydrate; Cold seep; Authigenic carbonate; Bay of Bengal; AMO; Chemosynthetic community. |
| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00218/32911/31414.pdf |
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| Gauthier, Olivier; Sarrazin, Jozee; Desbruyeres, Daniel. |
| Our knowledge of species diversity in deep-sea chemosynthetic communities has come a long way since their discovery in the late 1970s, However, their study poses serious challenges that are linked to their remoteness, the variable selectivity and effectiveness of sampling tools in different conditions, a lack of consensus on the size compartments and sieve size used in practice, and the persistent discovery of species that are previously unknown to science. Still, with increasing accessibility and new sampling tools, quantitative data are becoming both more frequent and extensive, reducing limitations in the estimation and comparison of species diversity. Here, we review the literature for common difficulties encountered in the measurement and comparison... |
| Tipo: Text |
Palavras-chave: Deep-sea ecosystems; Chemosynthetic community; Species diversity; Richness; Evenness; Rarefaction; Diversity profiles; Diversity ordering; Alpha diversity; Statistical analysis. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00001/11274/7842.pdf |
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